Intrinsic flame-retardant epoxy resin, preparation method and application thereof

Abstract

This invention discloses an intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base structures, its preparation method, and its applications, belonging to the field of flame-retardant polymer materials technology. The intrinsic flame-retardant epoxy resin of this invention simultaneously contains phthalonitrile units, Schiff base units, and epoxy functional groups in its molecular structure. Its preparation method includes: obtaining an intermediate through a nucleophilic substitution reaction of nitrophthalonitrile with aminophenol, followed by Schiff base condensation with dihydroxybenzaldehyde, and finally reacting with epichlorohydrin to introduce epoxy groups. This resin combines the condensed-phase charring effect of phthalonitrile with the gas-phase flame-retardant effect of Schiff bases, producing a synergistic effect. When used as an intrinsic resin or additive in epoxy resin compositions, as an intrinsic resin, the cured product exhibits excellent flame-retardant properties. As an additive, it can improve the flame retardancy and mechanical properties of epoxy resin while maintaining thermal properties, exhibiting excellent flame-retardant efficiency.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant materials technology, specifically relating to a flame retardant epoxy resin, and more particularly to an intrinsic flame retardant epoxy resin containing phthalonitrile and Schiff base structures, its preparation method, and its application in epoxy resins. Background Technology

[0002] Epoxy resins are widely used in many key areas of the national economy and defense industry due to their excellent comprehensive properties. However, their characteristics such as easy combustion and difficulty in self-extinguishing, as well as the problems of smoke, toxicity, and dripping that accompany combustion, restrict their application in high-end applications where safety regulations are becoming increasingly stringent.

[0003] To address this deficiency, flame retardants need to be added. Traditional flame retardants are mainly classified into halogenated, phosphorus-based, nitrogen-based, and inorganic flame retardants. Halogenated flame retardants have been restricted due to environmental concerns. While phosphorus-based flame retardants are safe and efficient, increasing phosphorus content can negatively impact the thermal properties of epoxy resins. Although nitrogen-based and inorganic flame retardants are safe and non-toxic, high dosages when used alone can lead to a significant decrease in mechanical properties. Furthermore, the dispersibility and aging properties of flame retardants must be considered when adding them.

[0004] Intrinsic flame-retardant epoxy resins hold promise for solving the aforementioned problems by directly introducing flame-retardant functional groups into the epoxy resin molecular backbone through chemical synthesis. Researchers have explored various aromatic heterocyclic structures containing nitrogen, phosphorus, and silicon as potential intrinsic flame-retardant units. Among them, phthalonitrile structures, due to their ability to form highly stable aromatic heterocyclic crosslinking networks at high temperatures, have shown potential to improve the thermal stability and char formation of materials; while Schiff base structures, due to their potential to release non-flammable gases upon heating, are considered to have gas-phase flame-retardant effects. However, existing technical solutions mostly focus on introducing a single type of flame-retardant structural unit. These single-structure modified epoxy resins often have significant shortcomings in one aspect, such as flame-retardant performance, the degree of improvement in thermomechanical properties, or compatibility with general curing processes, making it difficult to meet the increasingly stringent requirements for the comprehensive performance of materials.

[0005] Therefore, developing an intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base structures, and achieving the synergistic effect of the two flame-retardant structures through molecular design, can resolve the contradiction between flame-retardant efficiency, thermal stability, mechanical properties and curing process in existing technologies. This has important theoretical and practical significance for expanding the application of epoxy resins in high-end flame-retardant fields. Summary of the Invention

[0006] To address the problems of poor flame retardant effect and poor mechanical properties of existing intrinsically flame-retardant epoxy resins, this invention provides an intrinsically flame-retardant epoxy resin containing phthalonitrile and Schiff base structures. The intrinsically flame-retardant epoxy resin of this invention combines the structures of phthalonitrile and Schiff base, exhibiting good thermal stability, high char formation rate, excellent flame retardant properties, and significantly improved mechanical properties.

[0007] Specifically, the present invention provides the following technical solutions: The first aspect of the present invention is to provide an intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base structures, the intrinsic flame-retardant epoxy resin having the molecular structural formulas shown in formulas (I) to (IV): (Ⅰ); (ⅠⅠ); (ⅠⅠⅠ); (IV).

[0008] The compounds shown in formulas (I) to (IV) achieve excellent flame retardant effects through the synergistic effect of condensed phase char formation by phthalonitrile and gas-phase flame retardancy by Schiff base. Different substituent positions only change the steric hindrance of the molecule, without affecting the functional group activity and the synergistic flame retardant mechanism.

[0009] A second aspect of the present invention is to provide a method for preparing an intrinsically flame-retardant epoxy resin containing phthalonitrile and Schiff base structures, comprising the following steps: S1: Under an inert atmosphere, a nitro-containing phthalonitrile compound and an aminophenol compound are reacted in a first organic solvent in the presence of an acid-binding agent to obtain intermediate compound A; S2: Under an inert atmosphere, the intermediate compound A obtained in step S1 is reacted with a dihydroxybenzaldehyde compound in a second solvent to obtain a bifunctional intermediate compound B. S3: Under an inert atmosphere, the bifunctional intermediate compound B obtained in step S2 is reacted with epichlorohydrin in the presence of a catalyst, and then treated with an alkaline solution to obtain the intrinsic flame-retardant epoxy resin.

[0010] In a preferred embodiment, the nitro-containing phthalonitrile compound is 4-nitrophthalonitrile; In some embodiments, in step S1, the aminophenolic compound is selected from a combination of p-aminophenol and m-aminophenol; In some embodiments, in step S1, the first organic solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone; In some embodiments, in step S1, the acid-binding agent is selected from one or a combination of potassium carbonate, sodium carbonate, and triethylamine; preferably, it is potassium carbonate.

[0011] Further, step S1 is carried out at 50~90 °C for 4~12 hours. In some embodiments, the reaction temperature of step S1 is 70 °C~90 °C, and the reaction time is 6~10 h.

[0012] In some embodiments, in step S1, the molar ratio of the nitro-containing phthalonitrile compound to the aminophenol compound is 1:(1~1.5). In a preferred embodiment, the molar ratio of 4-nitrophthalonitrile to the aminophenol compound is 1:1.2. In a preferred embodiment, in step S1, the molar ratio of the acid-binding agent to the amino-containing phenolic compound is 1.5:1; the acid-binding agent and the amino-containing phenolic compound form a sodium phenolate structure.

[0013] In a preferred embodiment, in step S1, the nucleophilic substitution reaction is carried out at 90 °C for 4 hours; In a preferred embodiment, in step S1, the nucleophilic substitution reaction is carried out at 50°C for 12 hours.

[0014] In some preferred embodiments, in step S1, the amount of organic solvent used is 1 g raw material: 3~10 mL solvent, specifically, the amount of organic solvent used is 1 g phthalonitrile or amino-containing phenolic compound dissolved in 5~20 mL solvent; preferably, the amount of organic solvent used is 1 g raw material: 5 mL solvent.

[0015] In some embodiments, in step S2, the dihydroxybenzaldehyde compound is selected from one or a combination of 2,4-dihydroxybenzaldehyde and 3,4-dihydroxybenzaldehyde. Further, in step S2, the reaction temperature is 50~75 °C, and the reaction time is 5~10 hours. In some embodiments, the reaction temperature in step S2 is 50 °C~70 °C, and the reaction time is 6~10 hours. In some embodiments, in step S2, the molar ratio of the intermediate compound A to the dihydroxybenzaldehyde compound is 1:(1~1.5).

[0016] In some preferred embodiments, in step S2, the Schiff base reaction is carried out using ethanol as a solvent, and the amount of organic solvent is based on 1 g of aminophthalonitrile intermediate or dihydroxybenzaldehyde dissolved in 8-20 mL of solvent, specifically, the amount of organic solvent is based on 1 g of aminophthalonitrile or dihydroxybenzaldehyde dissolved in 8-20 mL; preferably, the amount of organic solvent is 1 g raw material: 12 mL solvent.

[0017] In some embodiments, in step S3, the catalyst is a quaternary ammonium salt, preferably tetrabutylammonium bromide; The molar ratio of intermediate compound B to epichlorohydrin is 1:(30~60); The reaction temperature in step S3 is 60℃~90℃, and the reaction time is 6~12 h.

[0018] In some preferred embodiments, in step S3, the amount of epichlorohydrin used is 1 g of an intermediate containing phthalonitrile and Schiff base dissolved in 7-14 mL of solvent; specifically, the amount of organic solvent used is 1 g of intermediate dissolved in 7-14 mL of solvent; preferably, the amount of organic solvent used is 1 g of raw material: 12 mL of solvent.

[0019] A third aspect of the invention provides the use of the intrinsically flame-retardant epoxy resin containing phthalonitrile and Schiff base structures in the preparation of flame-retardant epoxy resin materials. The intrinsically flame-retardant epoxy resin containing phthalonitrile and Schiff base structures is used as an intrinsically flame-retardant resin or an additive flame retardant.

[0020] The present invention provides a flame-retardant epoxy resin composition comprising a curing agent and an epoxy resin component, wherein the epoxy resin component includes the intrinsically flame-retardant epoxy resin and an epoxy resin prepolymer; the intrinsically flame-retardant epoxy resin accounts for 5% to 100% of the total mass of the epoxy resin component; optionally, the intrinsically flame-retardant epoxy resin accounts for 10% to 100%, 15% to 100%, 20% to 100%, 30% to 100%, 40% to 100%, 50% to 100%, 60% to 100%, or 70% to 100% of the total mass of the epoxy resin component.

[0021] Furthermore, the flame-retardant epoxy resin composition comprises the following substances in parts by weight: 0-100 parts of epoxy resin prepolymer; 20-90 parts of curing agent; 10-100 parts of intrinsic flame-retardant epoxy resin.

[0022] Furthermore, the epoxy resin prepolymer is selected from one or a combination of several of glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, or alicyclic epoxy resins. In some embodiments, the curing agent is selected from one or a combination of several of acid anhydrides, polyamines, dicyandiamides, or phenolic resins.

[0023] Another aspect of the present invention is to provide a method for preparing the flame-retardant epoxy resin composition described above: the intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base is stirred with an epoxy resin prepolymer to form a homogeneous liquid, and then a curing agent is added and stirred until dissolved to obtain the flame-retardant epoxy resin composition. Furthermore, the flame-retardant epoxy resin composition can be cured to obtain a flame-retardant epoxy resin cured product.

[0024] In some embodiments, the intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base is stirred with an epoxy resin prepolymer at 90-120 °C for 5-15 minutes to form a homogeneous liquid.

[0025] In some embodiments, the curing process includes pouring a homogeneous liquid containing a curing agent into a mold, placing it in a drying oven, and curing it for 1-2 hours at 100 ℃, 120 ℃, 140 ℃, 160 ℃, 180 ℃, 200 ℃, and 230 ℃ respectively.

[0026] Beneficial effects: (1) The intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base of the present invention integrates phthalonitrile unit, Schiff base unit and epoxy functional group in its molecular structure; it can exert the synergistic flame-retardant effect of condensed phase and gas phase. The epoxy resin cured product prepared by applying it to epoxy resin has good flame-retardant effect, and also has good smoke suppression and char formation.

[0027] (2) The intrinsically flame-retardant epoxy resin containing phthalonitrile and Schiff base described in this invention has good compatibility and is easily dispersed in the resin matrix, improving the stability of the cured epoxy resin during processing. This also helps to improve the thermal properties (thermal decomposition temperature, T0) of the cured epoxy resin. g To improve the mechanical properties of epoxy-cured products with minimal impact.

[0028] (3) The preparation method of the intrinsic flame-retardant epoxy resin of the present invention has mild conditions, simple steps, and high yield (up to 84%); it has good repeatability and scalability.

[0029] (4) Epoxy cured products prepared by using the compounds of the present invention as resin matrices or additives, while maintaining excellent processability and matrix mechanical properties, possess excellent comprehensive properties: limiting oxygen index (LOI) > 35%, vertical burning reaches V-0 level, char residue is significantly improved (> 50%), and glass transition temperature (T0) g This allows it to be maintained or improved. Attached Figure Description

[0030] The accompanying drawings are provided to further illustrate the present application and form part of the specification. They are used together with the embodiments of the present application to explain the application and do not constitute a limitation thereof. In the drawings: Figure 1 The 1H NMR spectrum of intermediate A obtained in Example 1 of this invention; Figure 2 The 1H NMR spectrum of intermediate B obtained in Example 1 of this invention; Figure 3 The 1H NMR spectrum of the intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base prepared in Example 1 is shown. Figure 4 Thermogravimetric curves of the flame-retardant epoxy resin cured products obtained in Examples 2, 3, and Comparative Example 1 of this invention are shown. Figure 5 The thermomechanical properties of the epoxy resin cured products obtained in Examples 2, 3 and Comparative Example 1 of this invention are shown. Detailed Implementation

[0031] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification. Many specific details are set forth in the following description to provide a thorough understanding of the present invention; however, the present invention may also be implemented in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; the reagents and instruments described, unless otherwise specified, are commercially available.

[0032] The preparation method of one of the intermediates of the intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base according to the present invention specifically includes the following steps: Step 1: First, add 52.3 g (0.48 mol) of p-aminophenol to a three-necked flask equipped with a mechanical stirrer and nitrogen gas. Add 300 mL of N,N-dimethylformamide and stir to dissolve. Then add 99.4 g (0.72 mol) of potassium carbonate and stir at 40 °C for 30 minutes. Next, add 69.2 g (0.40 mol) of 4-nitrophthalonitrile to the three-necked flask and heat to 80 °C and stir for 6 hours. After the reaction is complete, add 8.0 g (0.2 mol) of sodium hydroxide to 500 mL of deionized water to prepare a dilute alkaline solution. While stirring, add the reaction solution dropwise to the alkaline solution. Filter the liquid to obtain a filter cake. Wash the filter cake several times with deionized water to obtain the reaction intermediate with a yield of 95%. The molecular structure of the amino-containing phthalonitrile intermediate compound (intermediate A) is shown below, and its 1H NMR spectrum is shown below. Figure 1 As shown.

[0033] The reaction equation is as follows: Step 2: Weigh 35.2 g (0.15 mol) of the amino-containing phthalonitrile intermediate and 27.6 g (0.2 mol) of 2,4-dihydroxybenzaldehyde into a three-necked flask equipped with a mechanical stirrer and nitrogen gas. Add 350 mL of ethanol solution and stir to dissolve. Then heat to 70 °C and stir for 6 h. After the reaction is complete, filter the reaction system to obtain a filter cake. Wash with ethanol to obtain a bright yellow powder with a yield of 92%, which is the intermediate containing phthalonitrile and Schiff base (intermediate B). Its 1H NMR spectrum is shown below. Figure 2 As shown in the figure. The molecular structure of this intermediate is shown below, and it is named PNDBA.

[0034] The reaction equation is as follows: Step 3: First, 21.3 g (0.06 mol) of the intermediate PNDBA containing phthalonitrile and Schiff base, and 1.9 g (0.006 mol) of tetrabutylammonium bromide were added to a three-necked flask equipped with a mechanical stirrer and nitrogen. 350 mL of epichlorohydrin was added and stirred to dissolve the mixture. The temperature was raised to 80 °C and the reaction was carried out for 8 hours. Then, a 40 wt% aqueous solution was prepared with 9.6 g of sodium hydroxide and added dropwise to the reaction system. The reaction was continued at 80 °C for 3 hours. The reaction solution was then washed three times with deionized water. Magnesium sulfate was added to adsorb the remaining water, and excess epichlorohydrin was removed by rotary evaporation to obtain a viscous brownish-red liquid, which is the intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base, named PNDEP (i.e., the compound of formula (I)).

[0035] The reaction equation is as follows: .

[0036] The preparation methods and reaction conditions of compounds of formula (ⅠⅠ), (ⅠⅠⅠ), and (ⅠV) are basically the same as in Example 1. The corresponding compounds can be obtained by adjusting the reactants according to the preparation method of Example 1.

[0037] Example 2: Preparation of intrinsically flame-retardant cured epoxy resin (as resin matrix) The preparation method of the intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base according to the present invention includes the following steps: 100g of the intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base prepared in Example 1 was stirred at 120°C for 10 minutes. Then, 21.20g of curing agent (4,4'-diaminodiphenylmethane) was added and stirred until dissolved. The solution was then quickly poured into a preheated stainless steel mold. The mold was then placed in a forced-air drying oven and cured for 2 hours at 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, and 230°C respectively. After cooling, the flame-retardant epoxy resin sample was obtained.

[0038] Example 3: Preparation of intrinsically flame-retardant cured epoxy resin (as an additive) The method for preparing the flame-retardant epoxy resin of the present invention includes the following steps: 20g of the intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base prepared in Example 1 was stirred with 100g of epoxy resin prepolymer at 100°C for 15 minutes to form a homogeneous liquid. Then, 29.48g of curing agent (4,4'-diaminodiphenylmethane) was added and stirred until dissolved. The solution was then quickly poured into a preheated stainless steel mold. The mold was then placed in a forced-air drying oven and cured for 2 hours at 100°C, 120°C, 140°C, 160°C, 180°C, and 200°C respectively. After cooling, the flame-retardant epoxy resin sample was obtained.

[0039] Comparative Example 1: Preparation of Cured Ordinary Epoxy Resin 100g of epoxy resin prepolymer and 25.28g of curing agent (4,4'-diaminodiphenylmethane) were mixed at 90℃ to form a homogeneous liquid. The mixture was quickly poured into a preheated stainless steel mold, and then the mold was placed in a forced-air drying oven and cured at 100℃, 120℃, 140℃, 160℃ and 180℃ for 2 hours each. After cooling, epoxy resin samples were obtained for further comparative testing.

[0040] Performance Testing and Results Analysis The performance of the samples prepared in Example 2, Example 3 and Comparative Example 1 was tested, and the results are shown in Table 1.

[0041] Table 1 Comparison of comprehensive performance of epoxy resins like Figure 4 , Figure 5 Table 1 shows that, comparing Examples 2 and 3 with Comparative Example 1, the epoxy resin prepared by this invention can improve the flame retardancy of epoxy resin, whether used as an intrinsic flame-retardant epoxy resin or as an additive flame retardant (all materials achieve V-0 flame retardancy rating). Thermogravimetric analysis curves are shown below. Figure 4 As shown; Example 2 exhibited a char residue rate of 52% at 800°C, significantly higher than the 14% of Comparative Example 1, and Example 3 also showed an increased char residue rate of 20%, indicating that PNDEP can effectively enhance the char-forming ability of the matrix resin. Dynamic thermomechanical analysis (DMA) curves are shown below. Figure 5 As shown. Example 2, T g It can reach 214℃, which is significantly improved compared to ordinary epoxy resin (by 32℃). The T in Example 3... g The temperature is very close to 182°C in Comparative Example 1, which indicates that adding a small amount of the intrinsic flame-retardant epoxy resin of this invention can achieve V-0 flame retardancy while maintaining the heat resistance of the matrix resin, thus solving the defect of traditional flame retardants that seriously damage the thermal properties of materials.

[0042] In summary, this invention provides an intrinsically flame-retardant epoxy resin containing phthalonitrile and a Schiff base, its preparation method, and its applications. Based on a nitro-containing phthalonitrile compound (e.g., 4-nitrophthalonitrile), an intrinsically flame-retardant epoxy resin containing phthalonitrile and a Schiff base is obtained through a Schiff base reaction with benzaldehyde containing dihydroxyl groups and a ring-opening-ring-closing reaction with epichlorohydrin. The successful molecular design achieves synergistic flame retardancy in both the condensed and gas phases. This compound can be used alone as a high-performance intrinsically flame-retardant resin, exhibiting excellent thermal and flame-retardant properties (high TT). g It has high carbon residue; it can also be used as a high-efficiency flame retardant additive. With a small amount of addition, it can give ordinary epoxy resin excellent flame retardancy, and has minimal impact on its key thermomechanical properties, showing great application potential.

[0043] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. An intrinsically flame-retardant epoxy resin containing phthalonitrile and Schiff base structures, characterized in that, The molecular structural formulas are shown in formulas (I) to (IV): (Ⅰ)； (ⅠⅠ)； (ⅠⅠⅠ)； (ⅠV)。 2. The method for preparing the intrinsic flame-retardant epoxy resin according to claim 1, characterized in that, Includes the following steps: S1: Under an inert atmosphere, a nitro-containing phthalonitrile compound and an aminophenol compound are reacted in a first organic solvent in the presence of an acid-binding agent to obtain intermediate compound A; S2: Under an inert atmosphere, the intermediate compound A obtained in step S1 is reacted with a dihydroxybenzaldehyde compound in a second solvent to obtain a bifunctional intermediate compound B. S3: Under an inert atmosphere, the bifunctional intermediate compound B obtained in step S2 is reacted with epichlorohydrin in the presence of a catalyst, and then treated with an alkaline solution to obtain the intrinsic flame-retardant epoxy resin.

3. The method for preparing the intrinsic flame-retardant epoxy resin according to claim 2, characterized in that, In step S1, The aminophenolic compounds are selected from a combination of p-aminophenol and m-aminophenol; And / or, the first organic solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone; And / or, the acid-binding agent is selected from one or more of potassium carbonate, sodium carbonate, and triethylamine; And / or, the reaction temperature in step S1 is 70℃~90℃, and the reaction time is 6~10 h; And / or, in step S1, the molar ratio of the nitro-containing phthalonitrile compound to the aminophenol compound is 1:(1~1.5).

4. The method for preparing the intrinsic flame-retardant epoxy resin according to claim 2, characterized in that, In step S2, The dihydroxybenzaldehyde compounds are selected from one or a combination of two of 2,4-dihydroxybenzaldehyde and 3,4-dihydroxybenzaldehyde. And / or, the reaction temperature in step S2 is 50℃~70℃, and the reaction time is 6~10 h; And / or, in step S2, the molar ratio of the intermediate compound A to the dihydroxybenzaldehyde compound is 1:(1~1.5).

5. The method for preparing the intrinsic flame-retardant epoxy resin according to claim 2, characterized in that, In step S3, The catalyst is a quaternary ammonium salt, preferably tetrabutylammonium bromide; And / or, the molar ratio of the intermediate compound B to epichlorohydrin is 1:(30~60); And / or, the reaction temperature in step S3 is 60℃~90℃, and the reaction time is 6~12 h.

6. The use of the intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base structure as described in claim 1, or the intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base structure prepared by any one of claims 2 to 5, in the preparation of flame-retardant epoxy resin materials.

7. The use according to claim 6, characterized in that, The intrinsic flame-retardant epoxy resin containing phthalonitrile and Schiff base structures is used as an intrinsic flame-retardant resin or an additive flame retardant.

8. A flame-retardant epoxy resin composition comprising a curing agent and an epoxy resin component, characterized in that, The epoxy resin component comprises the intrinsic flame-retardant epoxy resin as described in claim 1, and the intrinsic flame-retardant epoxy resin accounts for 5% to 100% of the total mass of the epoxy resin component.

9. The flame-retardant epoxy resin composition according to claim 8, characterized in that, Composed of the following substances in parts by mass: 0-100 parts of epoxy resin prepolymer; 20-90 parts of curing agent; 10-100 parts of intrinsic flame-retardant epoxy resin.

10. The flame-retardant epoxy resin according to claim 9, characterized in that, The epoxy resin prepolymer is selected from one or a combination of several of glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, or alicyclic epoxy resins. And / or, the curing agent is selected from one or a combination of several of acid anhydrides, polyamines, dicyandiamides, or phenolic resins.

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